Add the missing PNaCl atomicops support.

src/google/protobuf/stubs/atomicops_internals_pnacl.h

@@ -0,0 +1,73 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2012 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// This file is an internal atomic implementation, use atomicops.h instead.
+
+#ifndef GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_PNACL_H_
+#define GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_PNACL_H_
+
+namespace google {
+namespace protobuf {
+namespace internal {
+
+inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr,
+                                         Atomic32 old_value,
+                                         Atomic32 new_value) {
+  return __sync_val_compare_and_swap(ptr, old_value, new_value);
+}
+
+inline void MemoryBarrier() {
+  __sync_synchronize();
+}
+
+inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr,
+                                       Atomic32 old_value,
+                                       Atomic32 new_value) {
+  Atomic32 ret = NoBarrier_CompareAndSwap(ptr, old_value, new_value);
+  MemoryBarrier();
+  return ret;
+}
+
+inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) {
+  MemoryBarrier();
+  *ptr = value;
+}
+
+inline Atomic32 Acquire_Load(volatile const Atomic32* ptr) {
+  Atomic32 value = *ptr;
+  MemoryBarrier();
+  return value;
+}
+
+}  // namespace internal
+}  // namespace protobuf
+}  // namespace google
+
+#endif  // GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_PNACL_H_